Nukovic, A. | Search bioRxiv

bioRxiv2026

Oxygen-generating cryogel vaccines help overcome tumor antigen tolerance and induce durable anti-tumor immunity in prostate cancer

Therapeutic cancer vaccines represent a promising approach to boost patients own immune system to fight cancer. However, many vaccine candidates have shown limited success in clinical trials in large part due to the insufficient antigen delivery to overcome tolerance and hypoxia mediated immunosuppressive mechanisms. Cryogel-based delivery scaffolds have emerged as a promising platform for cancer vaccines due to their biocompatibility and macroporous structure that allows for effective delivery to infiltrating antigen-presenting cells. However, these systems are limited by rapid, diffusion-mediated burst release of encapsulated recombinant proteins and local hypoxia-driven immunosuppression within the scaffold. Herein, we demonstrate that click conjugation of a tumor-associated protein within cryogel-based vaccines, combined with our new O2-generating platform (Click O2-CryogelVAX), helps overcome immune suppression and weak antigenicity and primes effective anti-cancer immune responses. Sustained antigen delivery promotes cellular memory and Th1-mediated anti-cancer responses. By reversing hypoxia-driven immunosuppression, O2 acts as a powerful co-adjuvant to enhance humoral immunity. Together, Click O2-CryogelVAX supports a robust antitumor response that inhibits tumor growth and prolongs survival in a therapeutic prostate cancer model. These findings support the further research and development of Click O2-CryogelVAX as an effective delivery platform for therapeutic cancer vaccines.

bioengineering↗

bioRxiv2023

Controlling pericellular oxygen tension in cell culture reveals distinct breast cancer responses to low oxygen tensions

Oxygen (O2) tension plays a key role in tissue function and pathophysiology. O2-controlled cell culture, in which the O2 concentration in an incubators gas phase is controlled, is an indispensable tool to study the role of O2 in vivo. For this technique, it is presumed that the incubator setpoint is equal to the O2 tension that cells experience (i.e., pericellular O2). We discovered that physioxic (5% O2) and hypoxic (1% O2) setpoints regularly induce anoxic (0.0% O2) pericellular tensions in both adherent and suspension cell cultures. Electron transport chain inhibition ablates this effect, indicating that cellular O2 consumption is the driving factor. RNA-seq revealed that primary human hepatocytes cultured in physioxia experience ischemia-reperfusion injury due to anoxic exposure followed by rapid reoxygenation. To better understand the relationship between incubator gas phase and pericellular O2 tensions, we developed a reaction-diffusion model that predicts pericellular O2 tension a priori. This model revealed that the effect of cellular O2 consumption is greatest in smaller volume culture vessels (e.g., 96-well plate). By controlling pericellular O2 tension in cell culture, we discovered that MCF7 cells have stronger glycolytic and glutamine metabolism responses in anoxia vs. hypoxia. MCF7 also expressed higher levels of HIF2A, CD73, NDUFA4L2, etc. and lower levels of HIF1A, CA9, VEGFA, etc. in response to hypoxia vs. anoxia. Proteomics revealed that 4T1 cells had an upregulated epithelial-to-mesenchymal transition (EMT) response and downregulated reactive oxygen species (ROS) management, glycolysis, and fatty acid metabolism pathways in hypoxia vs. anoxia. Collectively, these results reveal that breast cancer cells respond non-monotonically to low O2, suggesting that anoxic cell culture is not suitable to model hypoxia. We demonstrate that controlling atmospheric O2 tension in cell culture incubators is insufficient to control O2 in cell culture and introduce the concept of pericellular O2-controlled cell culture.

bioengineering↗